Propeller for flying machines



W. H. KELLY PROPELLER F'OR FLYING MACHINES July 17, 1923.

Filed Apr l 1917 4 Sheets-Sheet 1 VIIII/IIIll(llllllfllll wmmto'c July 17, 1923. 1 ,46L9l3 w. H. KELLY PHOPELLER FOR FLYING MACHINES Filed April 9, 1 1 4 Sheets-Sheet 2 fi gmuemto'r July 1.7, 1923. 1,461,913

W. H. KELLY PROPELLER FOR FLYING MACHINES Filed April 9 1917 4 Shets-Sheet 5 7 m 5/ July 17, 1923. 1,461,913

W. H. KELLY PROPELLER FOR FLYING MACHINES Filed April 9, 1917' 4 Sheets-Sheet 4 ill) ill

Patented July 17, 1%23.

titan WILLIAIII H. KELLY, O1 CHEYENNE, WYOMING.

PROPELLER FOR FLYING MACHINES.

- Application filed April To all wit-0122, 2'2 may concern:

Be it known that 1, WILLIAM H. KELLY, a citizen of the United States, residing at Cheyenne, in the county of Laramie and State of ll yoming, have invented certain new and useful Improvements in Propellers for Flying Machines; and i do declare the following to be a full, clear, and exact de scription of the invention, such; as will enable others skilled. in the art to which it appcrtains to make and use the same, reference being had to the accompanying drawings, and to the characters of reference marked thereon, which form a part of this specification.

My invention relates to improvements in propellers for flying machines. The object of the invention is to provide a propeller whose blades act both as propellers and at the same time as aeroplane sustaining surfaces just as do the wings of birds and other flying creatures. Another very important object and one which naturally and necessarily results from such construction, is to provide a )i'o1')eller so constructed that its blades in their forward flight cleave the air cdgewisc, but which. with reference alone to their movement about their axis, strike the air relatively tlatwise or broadside. In order to accomplish lhcseobjects, the blades are given such a pitch or are so attached to the shaft or axle upon which they flap or rotate, that a straight line connecting any two points in the front and rear edges of the blades which lie in a plane perpendicular to the longitudinal axis of the blade, will form with a plane passing longitudinally through the axis or shaft. and also through either of said points, an angle less than -l5 degrees. To make clear why this angle must be less than 4.5 degrees, I will suppose that the propeller is flying in a perfectly horizontal line with the axis pointed upward and forward at an angle of l5 degrees to the line of flight. Now if the blades. assuming that there are two, when viewed eudwise or from the side of the propeller, form angles of lzidegrees withthe axis one above and the other below the same as said blades extend transversely from front to rear edge, it will be understood, that one b ade will. present itself directly or squarely flatwise to the line of flight, that is perpendicular to said line of flight, thus acting as 1917. Serial N0. 16l),610.

a brake, while the other blade in this posi tion presents itself perfectly edgewise to the direction of flight. Thus it will be seen that in order that the blades may present themselves edgewise to the direction of the flight and thus act as combined aeroplanes and propellers, they must have such a pitch that a straight line connecting any two opposite points in their front and rear edges will form with a plane passing longitudinally through the axis and either of said points,an angle less than degrees. It is preferred to have a large portion of the blades as they extend transversely from front to rearedge, lie largely in or near a plane passing longitudinally through the axis and any given point in the front or rear edges of the blades. The blades as they e end transversely from front to rear may be eit ier straight, singly curved or doubly curved, Theblades thus disposed so that they will attack the air flatwise, with reference alone to their movement about their axis, will travel a great distance in their forward flight in each revolution, so that like natures wings their movement with relation to and about their axis is much slower than the speed of forward flight. In other words, the distance the wings or blades will travel in a given period of tiine say in one second, with reference alone to the movement about their axis, will be much less thanthe distance traveled in forward flight during such period of time.

Having briefly outlined my improvement as well as the function in a general way which it is designed to subserve, I will proceed to describe the same in detail, reference being made to the accompanying drawing. In this drawing I Fig. l. is a View of one form ,of my improved propeller viewed in the direction of its axis from a point in front of the same. This is also a view looking in the direction of arrow 1 Fig. 2.

Fig. 2 is a view looking in the direction of arrow 2 Fig. 1.

Fig. is a view of the same construction, but showing the propeller tilted so that its axis points upwardly at an angle of say d5 degrees to the horizontal. This maybe considered a view so far as the full linesare concerned, looking in the direction of arrow the blades is shown when at right angles to their full line position.

Fig. 4 is a section taken on the line 44. F ig. 1 looking toward the left.

Fig. 5 is a view similar to Fig. 1, but showing two of the propellers arranged to work in unison and rotating in opposite directions for stabilizing purposes, assuming that they are both mounted and properly arranged on. the same machine. In these views the auxiliary blades of the previous views whereby air channels from front to rear are formed, are omitted.

Fig. 6 is a view illustrating a slightly modified form of construction, being a view looking in the direction of the axis of a propeller.

Fig. 7 is a flatwise view of the propeller or a view looking right angles to the axis.

Fig. 8 is a section taken on the line 88 Fig. 7 looking toward the left.

Fig. 9 is a view similar to Fig. 7, but showing a slightly modified form of construction.

Fig. 10 is a cross section of one of the propeller blades taken 011 the line 1010 Fig. 9 looking toward the left.

Fig. 11 is a view similar to Fig. 9, but showing still another form or embodiment of invention.

Fig. 12 isa section taken on the line 12-12 Fig. 11 looking toward the left and changing the position of the axis so that it shall point upwardly at an angle of about 45 degrees.

Fig. 13 is a view similar to Figs. 9 and 11 and showing still another form of construction.

Fig. 14 is a section taken on the line 14-14. Fig. 13.

I Fig. 15 is a perspective showing a form whoseblades are longitudinally straight, but are provided with channels on both sides and have both the front and rear edges curved. V

Fig. 16 is a section online 1616 of Fig. 15.

In all of these views the-shaft to which the propeller blades are secured, extends from the propeller rearwardly or in a direction. opposite the direction of flight. This explanation will aid in understanding the views where the shaft is variously disposed as occurs on all of the sheets of the drawing.

The same reference characters indicate the same parts in all the views.

Referring first to Figs. 1 to 4 inclusive, let the numeral 5 designate a propeller considered in its entirety and equipped with two blades 6 which extend outwardly in op posite directions from the shaft 7. These blades are longitudinally curved or concavo convex, the curve being such that the concave surfaces are always faced in the direction of rotation. In Fig. 1 the direction of rotation is indicated by the arrows (1. Hence in this view, the righthand wing or blade has its under-surface concave and its uppper surface convex, while the lefthand blade or wing has its upper surface concave and its lower surface convex. This longitudinal curvature of the wings or blades servesto prevent the outward or lateral travel of the air in a direction longitudinally of the wings or blades and laterally of the direction of flight. It is extremely important to guard against this lateral escape of the air, since the whole object of a propeller is to give movement in the direction of flight, and since the reaction due to'the escape of the air from the blades is in the direction of flight, the air should be made to escape in a direction rearward of the direction of flight, and the degree of efliciency of the propeller will depend upon the extent to which that result is attained. Hence in the form of construction shown in the views now under consideration, in addition to the longitudinal curvature of the blades, each blade is equipped with a number of transversely arranged auxiliary blades 8 which are spaced to form air channels arranged transversely of the blades, thus serving to direct the air rear- "ardly from the blade in order to attain the aforesaid result in the maximum degree. It will be understood that by the formation of these transverse channels. the air which strikes the blades will be directed rearwardly in direction parallel or approximately parallel with the direction of flight. This is the ideal condition sought to be attained by the peculiar longitudinal curvature of the main blades, this construction being supplemented by the auxiliary blades. Furthermore, these blades have relatively extensive surface 9 extending parallel or approximately parallel with the of the shaft. These portions 9 of the blades, constitute aeroplanes or sustaining elements, while these together with the curved portions 10 of the blades, are acted upon by the air for propulsion purposes thus combining the two functions, via, the aeroplane or sustaining function and the propeller proper or driving function. It will be noted that the free edges 12 f the curved or inclined portions 10 of the wings or blades extend upwardly on the downwardly moving side and downwardly on the upwardly moving side. The channels between the auxiliary blades 8 are designated by the numeral 13. In order to obtain the best results from a propeller of this construction, its position should be such that its axis is pointed upwardly at an angle of about 45 degrees to the direction of flight. being the position illustrated in Fig. 3 of the drawing, the arrow bin this case in dicating the direction of rotation. It will be noted that a straight line connecting any two points in the front and rear. edges of either blade, which lie in a planeperpendicular to the longitudinal axis of the blade will form with a plane passing through the axis ofrotation andone of, said points an angle of less than 45 degrees These lines inFig. 3 are designated by the numeral 14.

eferring now ioFigf5 it will be noted that the two propellers earhoif which I will designate by the numeral have longitudinally curved wings G, but that they are rights and leftsso to speak, that is, the propeller on the right has its bladesarranged precisely as the propeller inflFig. 1, while the propeller on the left in Fig. 5 hasiits blades arranged the reverse of the arrangement in Fig. 1 so far as longitudinal curva ture iszconcerned. It will be noted, however, that where the two propellers are arranged together on the same machine that they r0 tate in reverse directions as indicated by'the arrows 15. The blades of the propellers in F 5 have the curved surfaces 10 and the relatively large areas 9 which extend parallel or approximately parallel with the axis thus enabling the propellers to perform the aeroplane or sustaining function as well as the propeller function proper.

In the form of construction shown in Figs. 6, 7 and b the blades 6 have relatively large areas 16 whiclrextend parallel with the axis of the shaft, while their front edges are curved in thedirection of rotation and their rear edges are curved away from the direction of rotation as shown at 17 and 18. The air acting upon the curved forward surfaces 17 of these blades, will have a lifting effect, while the air acting upon the curved surfaces 18 in the rear will have a propelling efifect or result in applyinga driving force in the direction of flight. In the construction shown in Figs'G, 7 and 8, the blades are not longitudinally curved, but they are transversely curved atthe front and rear edges and have a relatively large intervening transverse surface which is parallel with the axis of the propeller. In the form of construction shown-in Figs. 9 and 10, the area 19 of the blade extends parallel with the axis from'the front to a point 20 near the rear from which it is curved rather abruptly away fronithe direction of rotation as shown at 2 Again, in the construction shown in Fig. 11 the forward edge of the blade is curved toward the direction of rotation as shown at 22 from a point. 2-3, from which point rearwardly in a transvers direction the area 24 of the blade li parallel with the axis; Again, in the construc tion shown in Fig. 13 the two blades 6 have j their surfaces 25 each. lying in a single plane from frontto rear, the two wings or blades, however, each having a straight line connecting" any two points in its front and rear edges which lie in a plane perpendicular to sired.

the longitudinal axis of the blade so disposedthat it will form an angle of less than r5 with a plane passing through the, axis of rotation and one of said points. Fur- "1- -l -l 'ftl f fth r 1ei1noic,.t it p anes o no sin, aces 0 ese blades are so arranged that they cross each otherintermediate the portion of the shaft on which the propeller is mounted. i

. ittent-ionis calledto the factthat in all of the forms of construction except those shown in Fig. 5, the main blades have aux,- ihary blades 8 extending transversely thereacross forming channels for the air whereby the latter isdirected rearwardly and pro speed is obtained; and since no matter how greatthis forward speed may be, the surfaces'of the blades lying forward with reference to their rotary movement, will always meet with and accumulate pressure and the blades will continue to exert a forwardly propelling thrust. so that almost unlimited speed may be obtained. The enormous pres sure uponthe surfaces of the blades, obtained by the comparatively slow and fiatwise strokes as the blades rotate on their axis, .is brought under absolute control and utilized for propulsion. Now in obtaining this perfect control of the great pressure upon the blade surfaces, it is absolutely necessary to preventithe air from being fanned outwardly by. the fiatwise strokein a direction away from the axis. Since the reactionwhich results in propulsion will necessarily be in a direction opposite to that in which the air and pressure escape or is forced off. the surfaces of the blades, the air and pressure must be compelled to travel across the surfaces of the blades transversely and cannotbe permitted to follow the powerful tendency to be fanned outwardly and longitudinally of the blades. This can be accomplished only by making the blades 1 longitudinally concavo-convex,"'(see Figs. 1 to inclusive) the longitudinally concave surfaces being made to travel foremost with reference to the rotary movement; or this sam resultn'iaybe obtained by providinga series of channels 13 (see Figs. 1 to land 6 to. 13 inclusive) on the forwardly rotating 1 surfaces, hese channelsbein; made to exi tend transversely from the front to the rear edges of the blades. The longitudinally concave surface, if; of the necessaryudegree or the transversely extending channels,.will

of the blades, in spite of the great tendency ofthe flatwis'e striking blades to fan theair and cause the pressure to escape outwardly away from the axis. .Of the different shapes of transverse cross sections of .the blades, it is preferred to have the rear portions of the blades convex on their forwardly rotating surfaces as the'bladeslextend from front to rearedge, so that the rearportion of the blade will-exert a sort of sweeping action onthe air much like that of a "broom'or a fishs tail in action. The forwardportion of the'blade as it extends between front and rear edges, may be either approximately straight or may be curved in the opposite direction or manner to that in which the rear portion of the blade as it extends trans-- versely is curved, as heretofore described and as illustrated in the drawing. In other words, the surface of the blade lying forward with reference to its movement about the axis, may have its portion nearest the rear edge convex as it extends transversely of the blade, while its portion nearest the front edge is slightly concave'as itextends transversely of the blade, so that in trans verse cross section the blade forms a double or S-curve. Though the blades having transverse channels may be longitudinally straight, it is preferred to have them longitudinally concave-convex, the channelled surfaces being the longitudinally concave surfaces.

My improved .CODStIUC'tlOIl maybe em- 1 ployed as a marine propeller, but inthis case the blades HlHSt'lDG fiat both longitudinally and transversely as shown in F 1g; 14, or doubly curved transversely and lingitudlnally straight. Furthermore for this use they must be channeled on both surfaces.

Such a form is shown in Figs. 15 and 16.

When this propeller is at rest the blades are in position to attack the air flatwise when rotated. This creates the erroneous impression that the blades when they rotate do attackthe air flatwise. This is not true, because the instant the blades begin to ro tate they create a current of air which flows rearwardly apast. the blades, thus causing the blades to enter into the air, not flatwise, but ,edgewise, the degree of edgewise attack becoming greater as the speed of the rearwardly flowing air increases. This is best illustrated in the case ofthe flapping wings of a bird, there being'no difference, so far so that a straight points in the front-and rear edges of either gle; Where the forward flight greatly exceeds the flapping movement, the attack 7 would be ,niore edgewise than where the forward flight and flapping action were more nearly equal. Where they were ust equal,

the wing would attack 'theair at approxi inateiy forty-five degrees. Thisangular attack of thefiapping or rotating wing or blade upon'the air causes the pressure upon the active surface to escape readily and forcibly off the rear edge, thereaction resulting in a strong thrust of the wing forward in the direction of flight. The slight fiexureof the flexible wing ofa bird, both during the upward and downward flap, or the perinanent flexure of a rigid, artificial, rotating wing or blade causes the air, even if at tacked flatwise to escape off the rearedge, so that the rearward flow of air starts wi e whether the flying machine is standing still and the air being forced rearwardly past theblades of the propeller, or whether the maclnne IS in fl ght and the blades are entering into and attacking new and inidisturbedair,

the relation'between the blades and the surrounding air beingthe same in both cases.

l l'aving thus described my invention, what Iclain'i is: i i i 1. A propeller including blades arranged so that a straight line connecting any two points in the front and rear edges of either blade and lying in a plane perpendicular to the longitudinal axis of the blade, shall form with a plane passing longitudinally through the axis of rotation and'also through either of said points, anangle less than 45 degrees, the said blades having extending transversely thereof between front and rear in which lines from front to rear lie in planes parallel with the axis of rotation, the rear portion of the blade on the for wardly moving side considered with reference to itsrotary movement being transversely convex, and its forward edge transversely concave. i i

2. A propeller including blades arranged line connecting any two blade andlying in a plane 'ierpendicular-to the longitudinalaxis of the: blade. shall form with a plane passing longitudinally through the axis of rotation and alsothrough either of said points, an angle less than 45 degrees, the said blades having areas extending transversely thereof between front and rear in which lines from front to rear lie in planes parallelwith the axis O'flOt-fltlO1L/tl18 rear portion of each blade adjacent its rear edge being transversely concavo convex, the convex surface being on the forwardly nioving side during rotary action, while the forward.

portion ofjeither blade adjacent its forward edge 18 transversely concavo-convex, but

rangedso that a straight line connecting any two points in the front and rear edges of either blade and lying in a plane perpeiv dicular to the longitudinal axis of the blade, shall form with aplane passing longitudinally through the axis of rotation and also through either of said points, an angle less than 45 degrees,'the said blades having areas extending transversely between their front and rear edges, whose lines from front to rear lie in planes parallel wit-lithe axis of rotation, the forward portion of either blade immediately adjacent its forward edge being transversely concavo-convex,the concave surface being foremost considered with reference to rotary movement.

4c. A propeller including blades connected together at their inner extremities and arranged so that a straight line connecting any two points in the front and rear edges of either blade and lying in a plane perpendicnlar to the longitudinal axis of the blade, shall form with a plane passing longitudt nally through the axis of rotation and also through either of said points, an angle less than 45 degrees, the said blades having relatively large areas extending transversely thereof between front and rear in which lines from front to rear lie in planessubstan'tially parallel with the axisof rotation,

the rear portion of either blade being turned away from the direction of rotation to form a propelling surface.

5. A propeller, including blades having intermediate portions parallel with the axis of rotation and having their forward edges concave transversely of the blades.

6. A propeller, including blades having intermediate portions parallel with the axis of rotation and having their forward edges concave transversely and transverse channels on the faces of said blades.

7. A propeller having a shaft set-at an angle to the direction of flight and having thereon blades such that, of any two points in a blade, one point being in it ie front and the other in the rear edge and both points lying in a plane perpendicular to the longitudinal axis of the blade, the point in the front edge will be only slightly in advance of the point in the rear edge with reference to the rotary motion of the blade on its axis.

8. A propeller having a shaft set at an angle to the direction of flight and having thereon blades so arranged that a straight line connecting any two points in the front and rear edges located in a plane cutting the longitudinal axis of the blade at right an-- bles, will form with a plane passing longttudinally through the axis of rotation and also through either or" said points at angles less than' fo degrees, the said point in the front edge being only slightly forward of said point in the rear edge with reference to the direction ofrotary movementof the blade, each blade adjacent its front edge being transversely concaro-convexwith the transversely concave surface forward with reference to the direction of rotary movement'ofthe blade on itsaxisi l Y 9. A propeller having a shaft setat an angle to the direction offlight and having thereon blades so arranged that a straight line connecting two points inthe front and rear edges located in a plane cutting the longitudinal axis of theblade atright angles, will form with plane passing longitudinally through the axis of rotation and also through either of said point-s an angle less than 45 degrees, the said point inthe front edge being only slightly forward of said point in the rear edge with reference to the direction of rotary movement of the blade, each blade adjacent its front edge being transversely concavo-convex'with the trans versely concave surface forward with reference to the direction of rotary movement of the blade on its axis, the surface of each blade lying forward with reference to said rotary movement being provided with channels which extend from the front edge to the rear edge of each blade, and nearly as possible parallel to the axis of rotation.

10. A propeller, having a shaft set at an angle to the direction of flight and having thereon. blades so arranged that of any two given points in the front and rear edges located in a plane cutting the longitudinal axis of the blade at right angles the point in the front edge will be only slightly in ad- 1 vance of the point in the rear edge with reference to the rotary movement of the blade on its axis, each blade adjacent its front edge and on the surface lying forward with reference to said rotary movement be- 11 ing transversely concave and also concav, along the lines of intersection of the blade with planes passing perpendicularly through the axis of rotation. I

11. A propeller having a shaft set at an 115 angle to the direction of flight, and having blades which are greater in length than in breadth from front to rear edge, the pitch;. of each blade being such that the surface of each blade lying forward with reference to 130 its rotary movement on its axis will, on the downward stroke of the blade, be at an angle of incidence to the direction of flight.

12. A propeller having a shaft set at an angle to the direction of flight, and having blades which are greater in length than in breadth from front to rear edge, the pitch of each blade being such that a straight line connecting any two given points, one in the front edge and the other in the rear edge of each blade, and both points located in a plane perpendicular to the longitudinal axis of each blade, Will form with aplane passing longitudinally through the axis of rota- I tion and either of said points an angle much less than forty-five degrees. i a

13. A propeller having a shaft set at an angle to the direction of flight, and having blades which are greater in'length toward 1. the tip than in breadth from front to rear edge, the pitch of each blade being such that as the blade extends outwardly and horizontally from the axis of rotation the under surface ofeach blade is at an angle of incill dence to the direction of flight.

14 A propeller having a shaft set at such an angle as to point upwardly and forwardly with reference to the direction of flight, and having blades which are greater in length toward the tip than in breadth from front to rear edge, the pitch of each blade being such WILLIAM H. KELLY.

Witnesses MARY HIGGINS, ALBERT OBnrnn. 

